Artificial Intelligence Algorithm Improves Radiologist Performance in Skeletal Age Assessment: A Prospective Multicenter Randomized Controlled Trial.

Background Previous studies suggest that use of artificial intelligence (AI) algorithms as diagnostic aids may improve the quality of skeletal age assessment, though these studies lack evidence from clinical practice. Purpose To compare the accuracy and interpretation time of skeletal age assessment on hand radiograph examinations with and without the use of an AI algorithm as a diagnostic aid. Materials and Methods In this prospective randomized controlled trial, the accuracy of skeletal age assessment on hand radiograph examinations was performed with (n = 792) and without (n = 739) the AI algorithm as a diagnostic aid. For examinations with the AI algorithm, the radiologist was shown the AI interpretation as part of their routine clinical work and was permitted to accept or modify it. Hand radiographs were interpreted by 93 radiologists from six centers. The primary efficacy outcome was the mean absolute difference between the skeletal age dictated into the radiologists' signed report and the average interpretation of a panel of four radiologists not using a diagnostic aid. The secondary outcome was the interpretation time. A linear mixed-effects regression model with random center- and radiologist-level effects was used to compare the two experimental groups. Results Overall mean absolute difference was lower when radiologists used the AI algorithm compared with when they did not (5.36 months vs 5.95 months; P = .04). The proportions at which the absolute difference exceeded 12 months (9.3% vs 13.0%, P = .02) and 24 months (0.5% vs 1.8%, P = .02) were lower with the AI algorithm than without it. Median radiologist interpretation time was lower with the AI algorithm than without it (102 seconds vs 142 seconds, P = .001). Conclusion Use of an artificial intelligence algorithm improved skeletal age assessment accuracy and reduced interpretation times for radiologists, although differences were observed between centers. Clinical trial registration no. NCT03530098 © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Rubin in this issue.

Acute Limb Ischemia in an 8-Year-Old Patient: A Case Report.

We report the case of an 8-year-old patient with a history of nephrotic syndrome, who presented to the emergency department with right foot pain. The patient's mother described intermittent pain that woke her son from sleep and was accompanied by the foot turning purple and becoming cold to touch. Physical examination revealed capillary refill of over 10 seconds in the right and less than 2 seconds in the left foot. Ankle-brachial indices (ABIs) were 0.0 on the right and 0.96 on the left. The patient was admitted and started on therapeutic intravenous heparin. After consultation with his parents, right lower extremity angiography and thrombolysis was performed over 2 days. He subsequently underwent fasciotomy and amputation of the tip of all 5 toes. Eighteen months later, there is no leg length discrepancy, he is walking with foot inserts and has normal ABIs bilaterally.

Sonography-guided percutaneous liver biopsies in children.

OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of sonography-guided percutaneous core needle liver biopsy in infants and children. MATERIALS AND METHODS: We conducted a retrospective analysis of all patients who underwent sonography-guided percutaneous core needle liver biopsies over a 7.5-year period by pediatric interventionalists at a single tertiary center. RESULTS: A total of 597 procedures were performed in 470 patients (270 male and 200 female), with a mean age of 10.5 years (age range, 1 month-21 years). The main indications for biopsies were abnormal liver enzymes (n=129, 21.6%), grading and staging of chronic hepatitis B or C (n=105, 17.6%), evaluation of transplanted liver (n=111, 18.6%), iron overload (n=73, 12.2%), miscellaneous other diffuse parenchymal abnormalities (n=124, 20.7%), and focal hepatic lesions (n=55, 9.2%). The procedures were performed either under sedation (n=311, 52.1%) or general anesthesia (n=286, 47.9%). Diagnostic yield was obtained in 596 biopsies (99.8%) from an average of 2.4 cores in patients with diffuse disease (n=541, 90.6%) and 6.5 cores in patients with focal disease (n=55, 9.2%). Ten patients (1.7%) experienced a major complication, including pneumothorax (n=1, 0.2%), abdominal wall pseudoaneurysm (n=1, 0.2%), and symptomatic bleeding (n=8, 1.3%). Five of these children required transfusion, two were only admitted for observation, and one required surgical evacuation. There were no procedure-related deaths. Minor complications (n=49, 8.2%) included a symptomatic subcapsular hematoma (n=35) and stable small hemoperitoneum (n=9). CONCLUSION: Sonography-guided percutaneous core liver biopsy is a safe and effective procedure in children that has a high diagnostic yield and very low complication rate.

Sclerotherapy of abdominal lymphatic malformations with doxycycline.

PURPOSE: To assess the safety and efficacy of percutaneous image-guided sclerotherapy with doxycycline as primary treatment of intraabdominal lymphatic malformations (LMs). MATERIALS AND METHODS: Retrospective review was performed of all cases of abdominal, mesenteric, or retroperitoneal LMs referred to a single center that were subsequently treated with image-guided percutaneous sclerotherapy. RESULTS: Ten patients were included, of whom six were male. The mean age was 13 years (range, 2-28 y). Preprocedural cross-sectional imaging demonstrated a macrocystic malformation in nine patients and a mixed macrocystic/microcystic malformation in one. The malformation was accessed under sonographic guidance, followed by injection of opacified sclerosant agent under fluoroscopic guidance. A drainage catheter was placed in eight cases, in which sclerotherapy was repeated through the catheter for another 1 day (n = 2) or 2 days (n = 6). Doxycycline was reconstituted at 10 mg/mL, with a mean per-session dose of 608 mg (range, 80-1,000 mg) and a mean total dose of 1,230 mg (range, 80-3,000 mg). Peritoneal spill was identified in one case, but the patient remained asymptomatic. No other complications were encountered. Follow-up imaging was available in eight patients: complete resolution was seen in seven, with partial resolution in one. There was no recurrence of clinical symptoms in the follow-up period. CONCLUSIONS: Initial results indicate that percutaneous image-guided sclerotherapy of macrocystic intraabdominal LMs with doxycycline is a safe and effective procedure.

Angiographic demonstration of an aberrant abdominal umbilical artery in a patient with penoscrotal transposition and caudal regression.

Penoscrotal transposition (PST) is a rare congenital anomaly characterized by caudal location of the penis with respect to the scrotum. PST may be seen in isolation or associated with caudal regression syndrome. We present a case of an infant born with penoscrotal transposition, bladder agenesis, a solitary dysplastic kidney, and caudal regression. The patient developed anuria and was referred for angiography for preoperative planning for renal transplantation and genital reconstruction. Angiography demonstrated an aberrant abdominal umbilical artery, an anomaly classically associated with sirenomelia but also has been described in caudal regression.

Incidence and distribution of argininosuccinate synthetase deficiency in human cancers: a method for identifying cancers sensitive to arginine deprivation.

BACKGROUND: Argininosuccinate synthetase (ASS) was the first of two enzymes to convert citrulline to arginine. This pathway allowed cells to synthesize arginine from citrulline, making this amino acid nonessential for the growth of most mammalian cells. Previous studies demonstrated that several human tumor cell lines were auxotrophic for arginine due to an inability to express ASS. Selective elimination of arginine from the circulation of animals with these tumors is a potentially effective anticancer treatment. The purpose of these experiments was to determine the frequency of ASS deficiency and arginine auxotrophy in a variety of human malignant tumors. METHODS: The authors analyzed the expression of ASS by immunohistochemistry with a monoclonal antibody in a variety of human tumor biopsies. They found that the incidence of ASS deficiency varied greatly with the tumor type and tissue of origin. RESULTS: Melanoma, hepatocellular carcinoma, and prostate carcinoma were most frequently deficient in ASS. Some human cancers were almost always positive for ASS (e.g., lung and colon carcinomas). However, other human cancers, including sarcomas, invasive breast carcinoma, and renal cell carcinoma, also were sometimes ASS deficient. CONCLUSIONS: These data indicated that immunohistochemical detection of ASS may prove an effective means for determining ASS deficiency in malignant human tumors and for identifying patients most likely to respond to arginine deprivation therapy. Based on these results, human clinical trials using arginine-degrading enzyme therapy to treat patients with advanced melanoma or hepatocellular carcinoma have been initiated.

Biochemical characterization of the arginine degrading enzymes arginase and arginine deiminase and their effect on nitric oxide production.

BACKGROUND: Nitric oxide (NO) is a biomediator believed to be synthesized primarily from extracellular arginine. Various methodologies have been used to inhibit NO synthesis so as to elucidate its physiological and pathophysiological functions. Several investigators have utilized various argin ine degrading enzymes as a means of lowering extracellular arginine. Arginase, most commonly derived from mammalian sources, has been most often used. However, arginase has failed to inhibit NO synthesis. Therefore, a systematic biochemical characterization of arginase and arginine deiminase (ADI) derived from M. Hominus was undertaken. MATERIAL/METHODS: The murine macrophage cell line N-9 was treated with either arginase or arginine deiminase to determine the effect on intracellular and extracellular arginine and nitric oxide production. RESULTS: Arginase was found to have an alkaline pH optima(approximately 9.5) with little enzyme activity at physiological pH. In contrast, the pH optima of ADI was approximately 6.5, retaining >70% of its activity at physiological pH. ADI had more than 1000 fold higher affinity for arginine (Km approximately 30 KM for ADI vs approximately 45 mM for arginase), and was able to lower arginine levels to a much greater extent than arginase. ADI, unlike arginase, was effective in lowering extracellular arginine in tissue culture media and inhibit NO production by the murine macrophage cell line N-9 in response to gamma interferon and LPS stimulation. CONCLUSIONS: These data suggest that ADI may be useful for delineating the role of NO in a variety of biological systems as well as determining the role of extracellular arginine in its synthesis.